The invention relates in general to boring tools and more specifically to drill bits having particular application for plumbing and electrical installations as well as other more general drilling uses.
As those in the construction industry and building trades are well aware, a considerable amount of rough boring of framing, roofs, floors and ceilings is required to permit installation of plumbing pipes and electrical wiring conduits. However, heretofore known drilling bits have been designed to withstand the severe conditions under which such rough boring is effected. It frequently happens that a boring tool will strike a nail and become nicked and therefore have to be replaced unless it can be reground. Conventional drill bits, if replaced, are expensive and, of course, regrinding is also an expensive operation. Most of the presently known bits are not made substantially or ruggedly enough to remain sharp, but in fact must be sharpened or reground frequently. Additionally, known bits are prone to clog and therefore jam the drill. When shavings do not come out properly, the drill must be stopped and withdrawn, at times with considerable effort, and the hole cleaned so that the drilling operation can be resumed. Another problem is that a conventional bit will not take hold, as for instance when it must cut a hole drilled between two separate pieces of lumber, since the pieces will be inclined to separate. Additionally, conventional drill bits will catch or hang up if they emerge in such a way that part of the hole is finished and part is not. In other words, if the drill is through drilling on one side and not the other, the tendency in conventional bits is to jam. Because conventional Bits are constructed with a so-called flat or radially extending face, it is difficult to enter the wood at an angle, since the outer edges of the bit engage the wood before the lead screw. Furthermore, there is a tendency to misalign if the lead screw is not taking hold. So far as commercial drilling for plumbing and electrical installations is concerned, the tendency of bits to jam due to clogging or hanging up on nails is dangerous, since the drills themselves are large and can cause injury to the operator if stopped suddenly.
Prior art which the Examiner may wish to consider in this application will be found in U.S. Pat. Nos. 2,681,673; 2,752,965; 2,812,791; and 3,165,131. None of the cited patents is pertinent to the structure of applicants' invention.